The objective of this research is to describe the neurophysiological characteristics of inputs to the oculomotor nuclei from the vestibular nuclei and the pontine reticular formation. Unit activity will be recorded in these structures while the animal is undergoing sinusoidal rotations about a vertical axis or about an interaural axis to excite the respective semicircular canals and while the animal is simultaneously making voluntary eye movements in response to a moving target. In particular, preliminary results have shown that many vestibular units were strongly modulated with both vertical and horizontal eye movements and angular acceleration. These observations suggest that there is convergence of horizontal and vertical canal input. In addition, pontine units which pause for saccades and pontine units which burst for saccades will be recorded and evaluated in relation to saccadic and smooth eye movements as well as to visual sensitivity. BIBLIOGRAPHIC REFERENCES: King, W., Lisberger, S, and Fuch, A. Responses of Fibers in Medial Longitudinal Fasciculus (MLF) of Alert Monkeys During Horizontal and Vertical Conjugate Eye Movements Evoked by Vestibular or Visual Stimuli. Journal of Neurophysiology 39 No. 6, 1976. Evinger, L., Fuchs, A. and Baker, R. Bilateral Lesions of the Medial Longitudinal Fasciculus in Monkeys: Effects on the Horizontal and Vertical Components of Voluntary and Vestibular Induced Eye Movements. Experimental Brain Research Vol. 28, 1977, pp. 1-20.